1. Field of the Invention
The present invention relates to an optical plate, a method for manufacturing the optical plate, and a backlight module using the optical plate, the backlight module typically being used in apparatuses such as a liquid crystal display (LCD).
2. Discussion of the Related Art
In a liquid crystal display, liquid crystal is a substance that does not itself radiate light. Instead, the liquid crystal relies on light received from a light source, in order that the liquid crystal can provide displaying of images and data. In the case of a typical liquid crystal display device, a backlight module powered by electricity supplies the needed light.
Referring to FIG. 1, a typical direct type backlight module 10 is shown. The backlight module 10 includes a reflecting sheet 11, a plurality of light sources 12, a light diffusion plate 13, a light diffusion sheet 14, and a prism sheet 15. The light diffusion plate 13 is used for diffusing light rays from the light sources 12, and may have a multiplicity of light diffusion particles dispersed therein. The light diffusion plate 13 includes a light input surface 131 facing the light sources 12, and a light output surface 132 opposite to the light input surface 131. The reflecting sheet 11 is positioned under the light sources 12, and is configured for reflecting light rays back into the light diffusion plate 13. The light diffusion sheet 14 faces the light output surface 132 of the light diffusion plate 13, and is used for further diffusing light rays received from the light diffusion plate 13. The prism sheet 15 is positioned above the diffusion sheet 14. The prism sheet 15 is configured for collimating light rays emitted from the light diffusion sheet 14, thereby improving the brightness of light illumination provided by the backlight module 10.
Generally, the light diffusion plate 13, the light diffusion sheet 14, and the prism sheet 15 are in contact with each other, but with a plurality of air pockets existing at interfaces therebetween. In use of the backlight module 10, light rays pass through the air pockets, and some of the light rays undergo reflection at one or another of the corresponding boundaries of the interfaces. Thus the light energy utilization ratio of the backlight module 10 is reduced.
Therefore, what is needed is a new optical plate that has an improved light energy utilization ratio. What is also needed is a method for manufacturing such optical plate. What is further needed is a backlight module using such optical plate.